Treating rubber surfaces



Patented Mar. 22, 1927.

GEORGE I. WIKLE, OF MILWAUKEE, WISCONSIN, ASSIGNOB r 'rnn "new an...

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No Drawing.

My invention relates to the treatment of rubber surfaces and more particularly to the treatment of air bags which are used in the curing of tire casings. Before insertion in the raw casing the air bags are custom arily inflated and tested in a water bath and are then coated with a lubricating andprotecting substance 'to grevent adhesion of the bag to the casing an to prevent the migration of sulphur from the raw casing to the air bag during the curing process. Soapstone and mica are examples ofsubstances previously used for -this purpose. The use of such'substances either in powdered form or in the form of a paint is objectionable in that they rub and flake oil and are dusty and disagreeable to handle. .With their use the testing bath soon becomes filled and clouded with particles of the protective substance from previously. used bags, requiring frequent renewal of the testing bath.

' his one of the objects of my invention to provide a protective coating solution which shall be substantially clear and may therefore serve also as a testing bath, permitting the bag operation. v

A further object is to provide a lubricating and protective coating which will not rub or so flake off, which is clean to handle, and which I gives a more complete protection against the migration of sulphur to the bag.

I have found that amixture of hypo-sulphite ofsoda, glycerine and water give the desired results. Both the hypo-sulphite of soda and the glycerine possess the desired lubricating properties and the lycerine in addition tends to keep the rub er of the bag soft and in good condition. The hypo-sul- 40 phite of soda acts as an efiicient barrier to the migration of sulphur from the casing to the bag. The solution being in the form of a substantially clear, liquid can be used as the testing bath thereby saving the time and labor incident to separate testing and coat-' ing operations. The coating when dry has no tendency to flake or rub oil.

While the proportions of the materials used may be varied within comparatively end somewhat u on .wide limits and may de from which the ag the character of the stoc Application .flled April 8,

to be tested and coated at the same 1924. Serial 1%. *zoaaeofi v is made, I have found that two cerine, 5 parts of hypo-sulphite of soda and 9 parts of water by weight gives good results. The hypo-sulphite of soda is vfirst dissolved The bath is prefera ly heated when applied to' the bag, as in the heated condition ening agent.

parts of gly- Y in the water and the gl 'cerin'e. is thenadded- I have dezcribed my invention with:

Y 2. A coating solution for rubber surfaces comprising hypo-sulphite of soda and glycerme. y

3, A coating solution for rubber surfaces comprising hypo-sulphite of soda and glycerine 1m water.

4. A'coatingjsolution for rubber surfaces comprising substantially two parts of glycerine, five parts of hypo-sulphite "of soda and nine parts of water, by wei ht.

. 5. The processof treating a rulwber air bag which comprises inflating said bag and immersing it in a solution of hypo-sulphite of soda in water, to thereby simultaneously test and coat said bag.

6. The process of treating an air bag which comprises inflating said bag and immersin it in a solution ofphypo-sulphite of soda and glycerine in water, to thereby simultaneouslytest and coat said bag. 7 p

17. The process of treating a rubber air bag which comprises inflating'saidbag and v GEORGE E. WiK E 

